DE4338579C2 - Vehicle display device - Google Patents

Description

The invention relates to a display device for the Application in a vehicle and in particular a Display device for displaying information such as the Vehicle speed for the driver, what information as a virtual image at a distance from the eyes of the Driver appear.

Many of conventional vehicle display devices for Motor vehicles are, for example, under the dashboard of the Vehicle installed such that the display devices are out of the driver's line of sight when the driver the vehicle is driving. When the vehicle is driving, they move Driver's eyes mostly in the horizontal direction, since the Driver watching oncoming traffic. The driver has to however, move his eyes in a vertical direction when moving to the Example the one arranged under the dashboard Want to look at the speedometer. This is particularly so inconvenient when the vehicle is relatively high Speed moves and increases with the increase Vehicle speed progressively more uncomfortable. One way to solve the above problem is a head-up display provide in which the image representing the driving information is within the driver's field of vision while he is driving Vehicle drives. The image appears within the viewing area of the driver, but at a distance from the driver's eyes such that the driver's eyes are only a small Angle must move.

Japanese Patent Pre-Publication No. 60-192912 describes a vehicle display device for use in an automobile as shown in FIG. 6. A projector 1 projects an image characterizing vehicle information, for example vehicle speed, onto a mirror 2 b, which in turn reflects the image via an opening 4 a in the dashboard 4 to the inner surface of a windshield 3 . The windshield 3 then reflects the light into the driver's eyes E1, so that the driver sees a virtual image X1 at a distance behind the windshield 3 . A motor 2 a drives the mirror 2 b to change its inclination so that the position of the virtual image can be adjusted between positions X1 and X2. However, not only is the position of the virtual image moved vertically slightly, but the image can often be out of the driver's field of vision, so that the driver must move his eyes to E2 to view image X2. Accordingly, the driver must change his position to view the virtual images X1 and X2.

Sometimes head-up displays, particularly in good weather, are disadvantageous in that small differences in intensity between the outside light and the virtual image result in poor contrast of the virtual image. Furthermore, the virtual image appears in the driver's field of vision when the vehicle is traveling at high speed. This disturbs the driver's view. At night, the image tends to reflect on the outer surface and on the inner surface of the windshield 3 , so that the display image can often be doubled, resulting in poor display quality.

From DE 41 26 148 A1 is also a Vehicle display device for displaying one of the interior of a dashboard of a vehicle projected image known, the display device one of the Windshield of the vehicle's separate reflection surface which, at the lower end portion of the Windshield at an angle to this is arranged that from the inside of the dashboard projected image from the reflective surface into the eyes of the Driver is reflected, giving the driver a virtual picture looks behind the reflective surface.

The object is achieved by the invention, a Vehicle display device for use in motor vehicles to create the position of the virtual image  depending on the vehicle speed or the Outside light intensity adjustable, but for the driver is always visible from the same point of view.

This is according to the invention by the features according to the claim 1 solved.

A reflector is near the bottom of the windshield arranged of the vehicle. The reflector or the first one Reflective surface of the inner surface of the windshield a display image of one reflects over the reflector Projector or a luminous image display device, which under the dashboard is placed in the driver's eyes. The driver views the display image as a virtual image either behind the reflector or behind the Windshield. The virtual image is higher Position when it's behind the windshield than when it's behind the reflector. Of the For example, the reflector is made of a dark, opaque material or a mirror material an opaque one outside the reflecting surface Coating is attached.

A control device controls the vertical position of the virtual image such that the virtual image in higher Positions behind the windshield is seen if that Vehicle runs at high speed, and at lower speeds Positions behind the reflector is seen if that Vehicle runs at low speed. Additionally regulates the control device the position of the virtual image in such a way that it is seen in lower positions behind the reflector if the intensity of the outside light is outside of a predetermined range, d. H. during the day on a very beautiful day or during the night, in which cases that virtual image regardless of vehicle speed in lower positions can be seen behind the reflector can.  

Features and other advantages of the invention will be apparent from the Description of the preferred embodiment with reference to FIG the drawing easier to understand.

Fig. 1 shows an embodiment of the vehicular display apparatus according to the invention;

Fig. 2 shows another embodiment of the invention;

Figure 3 shows a light sensor used in the invention to sense the intensity of the outside light;

Fig. 4 shows the driver's field of vision while driving the vehicle;

Fig. 5 is a flowchart showing the steps for controlling the position of the virtual image; and

Fig. 6 shows a vehicle display device according to the prior art.

As shown in FIG. 4, a horizontal line h1 passes through point P1 in the driver's eye area and a horizontal line h2 passes through point P2. In a position S1, a line with a countersink angle of 5 ° relative to the horizontal line h1 crosses the windshield 3 . In a position S2, a line with a slope angle of 7 ° relative to the horizontal line h2 crosses the windshield 3 . The area B delimited by the positions S1 and S2 must be free of any obstacles in view so that the driver can drive the vehicle safely.

In a position S3, a line with a countersink angle of 1 ° relative to the horizontal line h1 crosses the windshield 3 . In a position S4, a line with a slope angle of 3 ° relative to the horizontal line h2 crosses the windshield 3 . The Japanese industry standard requires that no display image be reflected from area A delimited by positions S3 and S4.

The invention will be described in detail with reference to the drawing. Fig. 1 shows an embodiment of the display device according to the invention by the head-up display type for use in a motor vehicle. A projector 1 , a pivotable mirror 2 and a control device 10 are provided, all of which are arranged under the dashboard 4 . The control device 10 has a manual switch 7 , a speed sensor 6 which emits a vehicle speed signal, an electrical circuit 8 with a central computer, and a drive circuit 9 which drives a motor 2 a in accordance with the output signal of the electrical circuit 8 . The pivotable mirror 2 has the motor 2 a and a mirror 2 b. The manual switch 7 has, for example, two switches; one switch is an up switch and the other switch is a down switch (not shown). Continuous pressure on the up switch causes the motor 2 a to drive the mirror 2 b in such a way that the virtual image appears in higher positions. Continuous pressure on the down switch causes the motor 2 a to drive the mirror 2 b in such a way that the virtual image appears in low positions. The projector 1 projects a display image indicative of vehicle information, such as vehicle speed, onto the mirror 2 b. The mirror 2 b reflects the display image obtained from the projector 1 through an opening 4 a either onto the reflector 5 or onto the windshield 3 . The electrical circuit 8 receives the vehicle speed signal from the speed sensor 6 and controls the drive circuit 9 to pivot the mirror 2 b in accordance with the vehicle speed signal. The electrical circuit 8 also generates a signal for the projector 1 which is representative of the vehicle speed. Swiveling the mirror 2 b causes the light incident on it to be reflected at different angles of incidence and angles of reflection.

If the mirror 2 b is in position B, the mirror 2 b reflects the display image L1 projected by the projector 1 through the opening 4 a in the dashboard 4 onto the reflector 5 . The light L1 is then reflected into the driver's eyes E as a light L2. The driver sees the virtual image X1 in a low position behind the reflector 5 .

If the mirror 2 b is in the position A, the mirror 2 b reflects the display image L 3 projected by the projector 1 through the opening 4 a in the dashboard 4 onto the windshield 3 . The light L3 is then reflected from the inner surface of the windshield 3 as a light L4 that falls into the driver's eyes E. The driver sees a virtual image X2 in a high position behind the windshield 3 . The virtual image X2 is at a somewhat greater distance from the driver's eyes E than the virtual image X1. The driver can see both images X1 and X2 from the same sitting position.

The driver sees the virtual image X1 in low positions when the vehicle speed is below a predetermined value and the virtual image X2 in higher positions if the vehicle speed is above a predetermined value. The reflector 5 is arranged at a predetermined angle 8 relative to the dashboard 4 close to a lower region of the windshield 3 . The reflector 5 can be made of a dark, opaque material or of a mirror material to which an opaque coating is applied in addition to the reflecting surface.

The control device 10 can be designed such that it gradually varies the position of the virtual image behind the reflector 5 or the windshield 3 so that the virtual image is in lower positions when the vehicle is traveling at lower speeds and in higher positions. when the vehicle is traveling at higher speeds.

By actuating the manual switch 7 , the mirror 2 is driven by the motor 2 a, which enables the driver to see the virtual image in a desired position. The position of the display image can be stored in a memory in the electrical circuit 8 so that the display image can automatically appear in a predetermined position whenever the display device is switched on. The head-up display according to the invention is in particular designed such that the display image can never appear at the transition point between the windshield 3 and the reflector 5 .

A light sensor 12 shown in FIG. 3 can be arranged on the dashboard 4 shown in FIG. 4 , where outside light enters through the windshield 3 . The light sensor 12 emits to the electrical circuit 8 a light intensity signal which is proportional to the intensity of the outside light. The electrical circuit 8 checks the light intensity signal to determine whether the brightness outside the vehicle is inside or outside a predetermined range. If the brightness is outside the predetermined range, ie at night when it is very dark, or during the day if it is very bright, the virtual image is formed behind the reflector 5 regardless of the vehicle speed. The formation of the virtual image behind the reflector rather than behind the windshield eliminates the tendency to generate double images which occur at night due to reflection on the outer surface and the inner surface of the windshield.

Fig. 2 shows another embodiment of the vehicular display apparatus according to the invention. The vehicle display device corresponds to that of FIG. 1, except that the projector 1 , the mirror 2 a, and the motor 2 b are replaced by a luminous image display 11 . Components that correspond to those in Fig. 1 are given the same reference numerals. According to FIG. 2, a drive circuit 9 controls a motor 11 a for driving the light-emitting image display 11 so that a light-emitting surface 11 b is tilted relative to the windshield glass 3. The b projected from the light emitting surface 11 of image is reflected not only by the reflector 5, but also from the windscreen 3 in the form of a diverging beam. Therefore, a light control film 11 c is attached to the light emitting surface 11 b, which directs the rays in a predetermined direction. The b projected from the light emitting surface 11 of image is reflected from the inner surface of the windshield 3, behind which a virtual image is produced in relatively high positions X2, or from the reflector 5, behind which a virtual image is produced in relatively low positions X1.

The light emitted by the display device 11 can be reflected by a mirror (not shown), which in turn reflects the light onto the windshield 3 or the reflector 5 . The light sensor 12 in FIG. 3 can also be used in the embodiment according to FIG. 2.

The embodiment shown in FIG. 2 works similarly to the embodiment shown in FIG. 1. If the display device 11 is in the position C, the driver sees the image X1. If the display device 11 is in the position D, the driver sees the image X2.

In the embodiments according to FIGS. 1 and 2, the reflector 5 is mounted in an area below the point S1 at an angle Θ to the dashboard 4 . The inclination of the mirror 2 is controlled such that the display image is reflected either from the area between the points S1 and S3 in FIG. 4 or from the reflector 5 in accordance with the vehicle speed and the outside light intensity. Accordingly, the driver's field of vision is not disturbed by the displayed image while driving. The above-described embodiments allow the driver to view the virtual image X1 behind the reflector 5 or the virtual image X2 in the area between the points S1 and S3 while his eyes are in the area P1 to P2. The driver does not need to move his position or eyes to view the virtual images.

The operation of the control device 10 shown in FIG. 1 will be described with reference to the flow chart in FIG. 5. The vehicle display device is assumed to have a light sensor 12 . The program in Fig. 5 begins when the engine is started by the driver. In step S1, a random access memory (hereinafter referred to as RAM) stores in the electrical circuit 8 the vehicle speed signal which is output by the vehicle speed sensor 6 . In step S2, the RAM also stores the light intensity signal that indicates the intensity of the outside light outside the vehicle. In step S3, the vehicle speed signal is read out of the RAM and compared with a predetermined threshold value. If the answer in step S3 is NO, the program shifts to step S5. If the answer in step S3 is YES, the program shifts to step S4 in which the light intensity signal is read out from the RAM and a check is made to see if the light intensity is outside a predetermined range. If the answer in step S4 is YES, the program switches to step S5, in which the control device 10 controls the motor 2 a for driving the mirror 2 b in order to pivot it in such a way that the virtual image X1 is formed in a lower position becomes. If the answer in step S4 is NO, the program switches to step S6, in which the control device 10 controls the motor 2 a for driving the mirror 2 b in order to pivot it in such a way that the virtual image X2 is somewhat in a higher position closer to the driver than virtual image X1 is formed. The virtual images X1 and X2 are separated from each other by approximately 0 to 10 mm relative to the driver's eyes depending on their position.

In steps S1 and S2, the vehicle speed and the outside light intensity outside the vehicle are measured periodically. The position of the mirror is adjusted whenever the vehicle speed and the outside light intensity are measured, so that the position of the virtual image is updated periodically. In step S4, the drive circuit 9 checks the light intensity signal from the light sensor 12 to determine whether it is daytime on a very nice day or night when the intensity of the outside light is almost zero. If the light intensity signal has a value in the range from almost zero to a certain value, the control device 10 drives the mirror 2 b in accordance with the vehicle signal in such a way that the virtual image is formed accordingly in high positions or in low positions. On the other hand, even if the vehicle is traveling at high speeds, the virtual image is in low positions if the light intensity signal is not in the range from almost zero to the predetermined value.

On the reflective surface of the windshield 3 , for. B. a reflective coating can be applied to improve the visibility of the virtual images X1 and X2.

The opening 4 a in the dashboard 4 can be closed by a translucent glass plate or a translucent plastic plate as dust protection.

Claims (12)

1. Vehicle display device for displaying an image projected from the inside of a dashboard ( 4 ) of a vehicle
a first reflection surface, which is arranged near the lower end region of a windshield ( 3 ) and reflects the image projected from the interior of the dashboard ( 4 ) into a viewing point (E) from which the driver views the reflected image if the image is on the first reflection surface is incident; and
a second reflection surface ( 5 ) which is arranged at an angle to the first reflection surface and in a lower position than the first reflection surface such that the image projected from the interior of the dashboard ( 4 ) from the second reflection surface ( 5 ) at least in is essentially reflected into the same viewing point (E) if the image is incident on the second reflection surface; and
a controllable image projection means for projecting the image from the interior of the dashboard ( 4 ) either onto the first reflection surface or onto the second reflection surface ( 5 ),
wherein the driver sees a virtual image of the image projected from the interior of the dashboard ( 4 ) behind the first reflection surface or the second reflection surface ( 5 ). 2. The vehicle display device according to claim 1, in which the controllable Bildprojizierungsmittel, comprising a projector (1) for projecting the image, a mirror (2) for reflecting the projected image and a drive means (2a) for pivoting the mirror (2a) to to reflect the projected image either onto the first reflection surface or onto the second reflection surface ( 5 ). 3. The vehicle display apparatus according to claim 1, wherein the controllable Bildprojizierungsmittel a light image display is that applied (11) with a light control film (11 c) on a light emitting surface (11 b) of the luminous image displays (11), and a drive means (11 a) for Swiveling the luminous image display ( 11 ) in order to direct the image emitted by the luminous image display ( 11 ) either onto the first reflection surface or onto the second reflection surface ( 5 ). 4. Vehicle display device according to claim 1, wherein the second reflection surface ( 5 ) is made of dark, opaque material. 5. The vehicle display device according to claim 1, wherein an opaque coating is applied to the second reflection surface ( 5 ). 6. The vehicle display device according to claim 1, wherein the first reflection surface is an inner surface of the windshield ( 3 ). 7. The vehicle display device according to claim 6, wherein the first reflection surface is an inner surface of the windshield ( 3 ) with a surface that improves the visibility of the virtual image. 8. Vehicle display device according to one of claims 1 to 7, with a control device ( 10 ) for controlling the image projecting means for directing the image projected from the inside of the dashboard ( 4 ) forth onto the first reflection surface or onto the second reflection surface ( 5 ). 9. The vehicle display device according to claim 8, wherein the control device ( 10 ) has a vehicle speed sensor ( 6 ) for emitting a vehicle speed signal indicative of the vehicle speed, on the basis of which the control device ( 10 ) projects the image projection means for directing the interior of the dashboard ( 4 ) projected image depending on the vehicle speed on the first reflection surface or on the second reflection surface ( 5 ) is controlled. 10. The vehicle display device according to claim 9, wherein the control device ( 10 ) has the image projecting means for directing the image projected from the inside of the dashboard ( 4 ) when the vehicle speed signal is larger than a predetermined value onto the first reflecting surface and, when the vehicle speed signal is equal to or less than a predetermined value, is controlled on the second reflecting surface ( 5 ). 11. The vehicle display device according to claim 10, further comprising a light sensor ( 12 ) for emitting a light intensity signal which characterizes the intensity of the outside light in the vicinity of the windshield ( 3 ), the control device ( 10 ) receiving the light intensity signal from the light sensor ( 12 ) and controls the image projecting means for directing the image projected from the inside of the instrument panel ( 4 ) onto the second reflecting surface ( 5 ) when the light intensity signal is outside a predetermined range. 12. Vehicle display device according to one of claims 1 to 11, further comprising a manual switch ( 7 ) of the control device ( 10 ), by the actuation of which the image projection means for projecting the image can be driven either onto the first reflection surface or onto the second reflection surface ( 5 ).